Dynamoelectric machine



1942. 1.. P. GROBEL -Re."2

DYNAMOELECTRIC MACHINE Original Filed Aug. 1, 1939 2'4 2a Inventor:

" iQdi Lloyd F Grobel, \l L His Attor-n ey.

Reissued Aug. 18, 1942 DYNAMOELECTBIC MACHINE Lloyd r. Grobel, Schenectady, N. r, as... to General Electric Company, a corporation of New York Original No. 2,199,156, dated April 30,1940, Serial No. 287,785, August 1, 1939. Application for reissue November 15, 1940, Serial No. 365,817

Claims.

My invention relates to improvements in dynamoelectric machines, and particularly to an arrangement for minimizing the effect on the support of such machines of electromagnetic distortions and vibrations produced by a rotating magnetic field in such machines.

In certain types of dynamoelectric machines, considerable vibration may be set up in the sta tionary member of the machine by electromagnetic distortions which are created by the rotating magnetic field set up either by the rotatable member of the machine or by currents in a stationary member winding. This is particularly noticeable in two pole machines wherein the rotatable member is excited toprovide two magnetic poles which rotate within a'stationary member formed of magnetic material. The magnetic at- The stationary member of such a machine usually is provided with a laminated core in which the armature winding is arranged, and this assembly is mounted within a stationary supportingframe. It generally has been accepted that if the stiffness of the stationary member can be increased, the distortion thereof due to the rotating magnetic field may be reduced correspondingly. It has been found, however, that the rigid connection between the laminated core and the supporting frame does not provide an element having a deep beam stiflness, but rather the eiiect of a combination of two beams, one above the other, so that the resultant stiffness is merely the sum of the stiffness of the two elements. By actual tests, it has been found that the stiffness of a conventional laminated core in this type machine may be seven or more times that of a supporting frame, and therefore, the stiffening of the frame adds relatively little to the resultant stiffness of the stationary member of the machine.

In order to minimize the transmission of vibrations which are produced by the deformation of the laminated core of a stationary member in flexible beam springs for flexibly supporting the core upon the stationary supporting frame. These supporting springs are arranged to allow only relatively small deflections of the core due to the weight thereof, and also should avoid torsional resonance with any pulsating torques which may occur due to short circuits or unbalanced operation. It has been found that with two pole machines of this type, the stationary core vibrates with a four-node vibration which is not entirely radial, but that the nodal points have tangential displacements equal to about one-half the maximum radial displacements thereof. By supporting the laminated core within the stationary supporting frame on a flexible support which provides these characteristics, very little vibration will be transmitted to the stationary supporting frame, so that the transmission of magnetic vibratory forces to the foundation of the machine and noises incident thereto is substantially eliminated.

An object of my invention is to provide a dynamoelectric machine having an improved arrangement for supporting a stator core within a stator frame.

Another objectof my invention is to provide an improved flexible support for a magnetic core subjected to vibratory forces to minimize the transmission of such forces between the com and its supporting frame.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawing, Fig. 1 is an end view, partially broken away, of a dynamoelectric machine provided with an embodiment of my improved stationary member and supporting arrangement; Fig. 2 is a partial sectional view taken aions line 2-2 of. Fig. 1; Fig. 3 is a fragmentary view showing the relative arrangement of my improved supporting springs and their connection to the frame and core of the stationary member; Fig. 4 is a fragmentary enlarged end view of my improved flexible supporting elements and their connection to the frame and core as shown in Figs. 1 and 2; and Fig. 5 is a fragmentary side elevational view of the elements illustrated in Fig. 3.

Referring to the drawing, I have shown my this type of machine, I provide a plurality of invention in'connection with adynamoelectric machine having a rotatable member supported by a shaft ID. The rotatable member shaft is supported by pedestal bearings mounted in bearing housings i I arranged at each end of the machine. The rotatable member is provided with a magnetic core and an exciting winding, and is arranged to react electrodynamically with the stationary member, which is provided with an armature winding supported in a laminated magnetic core mounted in a stationary supporting frame. The laminated core includes a plurality of laminations l2 which is secured in assembled relation between end plates II at each end thereof and drawn together by a plurality of clamping bars M. A plurality of these bars is arranged in circumferentially spaced apart relation about the periphery of the laminated core, and each bar is formed with a groove l5 into which is secured a dovetail key It which also is fitted into a dovetail groove in the outer edge of the laminations [2. The outer ends ll of the clamping bars I4 are threaded and extend through openings formed in the end plates ii. The stiffness of the magnetic core may be adjusted by changing the pressure with which the laminations are clamped together. This pressure should be such that no substantial displacement occurs between adjacent laminations due to the electromagnetic distortion of the core in order to prevent chafing of the insulation on the armature winding arranged in the slots of this core. The

clamping pressure between the two end plates l3 may be varied by adjusting nuts it which engage the threaded ends ll of the clamping bars l4. The stationary supporting frame includes a plurality of annular supporting and stiffening plates l9 arranged in longitudinally spaced apart relation and secured within an outer wrapper plate 20. This supporting frame is provided with feet 2| on each side thereof, which are mounted upon a supporting foundation 22. To provide a flexible support which is substantially rigid longitudinally of the stationary member, I provide a mounting ring 23 welded to the inner edge of each of the plates l9 and a plurality of beam springs 24 arranged in longitudinally spaced apart sets and circumfcrentially spaced apart relation about the laminated core in each of these sets. These beam springs 24 are arranged in pairs, one on each side of a bar l4, andare formed with an enlarged portion adjacent each end and adjacent the central portion thereof. These beam springs 24 are secured adjacent the ends thereof to the supporting rings 23 by bolts 25 which extend through the enlarged ends and are secured adjacent the central portion thereof to the bars l4 by bolts 26, which extend through the enlarged central portion of the springs and through the clamping bars H. A spacing block 21 is arranged between each of the springs 24 and the adjacent clamping bar H to provide a slight clearance between the spring and the bar to allow for slight tangential flexing of the springs 24 without resulting in contact between the springs and the bars I4. In order to provide the desired radial and tangential flexibility to the supporting arrangement, the beam springs 24 are constructed so that their flexibility is substantially twice as great in a radial direction as in a tangential or circumferential direction with respect to the laminated core. This is obtained by making the springs 24 substantially twice as wide in a tangential direction as they are deep in a radial direction, as can flexibility of this spring supporting arrangement -in the tangential and radial directions is not my invention, but is'the invention of Chester W. Rice, and forms the subject of his copending application Serial No. 287,767, filed August 1, 1939, and assigned to the same assignee as this application. This arrangement of flexible springs provides a support for the laminated core which is substantially rigid longitudinally thereof and flexible radially and tangentially thereof, with the radial flexibility substantially greater than the tangential flexibility of the support. Furthermore, it allows for slight tangential and readily be seen from Figs. 3 and 5. The relative radial displacements of the laminated core within the stationary supporting arrangement, so that very little vibration is transmitted to the supporting frame and foundation 22.

While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means for supporting said core in said frame substantially rigidly longitudinally thereof, said supporting means being flexible substantially radially and tangentially of said core.

2. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means arranged at spaced apart points for supporting said core in said frame substantially rigidly longitudinally thereof, said supporting means being flexible substantially radially of said core.

3. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means. arranged at circumferentially and longitudinally spaced apart points for directly supporting said core in said frame, said supporting means being flexible radially of said core and providing a substantially rigidsupport longitudinally thereof.

4. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within saidframe, and means including beam springs for supporting said core in said frame, said springs being arranged to provide a substantially rigid core support longitudinally thereof.

5. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means including beam springs extending longitudinally of said core and arranged at circumferentially spaced apart points for flexibly supporting said core in said frame.

6'.'A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means including beam springs extending longitudinally ofsaidcoreandsecuredtosaidframeandto said core for supporting said core in said frame, saidbeamspringsupportingmeansbeingflexible radially of said core.

I. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means including beam springs arranged at longitudinally spaced apart points for flexibly supporting said core directly on said frame, said beam spring supporting means being flexible radially and tangentially oi said core.

8. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame and a core arranged within said frame, and means including a plurality of beam springs arranged at circumferentially and longitudinally spaced apart points'for supporting said core in said frame substantially rigidly longitudinally thereof, said beam spring supporting means being flexible radially ,of said core.

9. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame element and a core element arranged within said frame, and means including beam springs secured adjacent the ends thereof to one of said elements and secured intermediate the ends thereof to the other of said elements for supporting said core element directly on. saidv frame element.

10. A dynamoelectricmachine having a rotatable member and a stationary member, said stationary member being provided with a frame element and a core element arranged within said frame, and means including a plurality of circumferentially spaced apart beam springs securedadjacent theends thereofto oneof said elements and secured intermediate the ends thereof to the other of said elements for supporting said core element directly on said frame element, said beam spring supporting means being flexible radially of said core element.

11. A dynamoelectric machine having a rotatincluding pluralityofbeamspringssee'urerlto meat.

saidframeadjacenttheendsthereotandtoaaid ooreintennediatetheends thereofforsupportmerit, a laminated core element arranged within.

. 3 ingsaid coredirectlyonsaidframesaidbeam snrinas sarraneedinspaced apart sets and being arranged in circumferentiallyspaeedapart relatlonineachof saidsets.

12. A machine having a rotatable member and a stationary member, said stationary member being provided with a frame, a laminated core arranged within said frame, meansforsecuringandretainingsaidlaminated core in relation, and means secured tosaidframeandtosaidcoreassemblyretaining means for flexibly supporting said core directly on said frame.

13. A dynamoelectric machine having a rotatable member and a stationary member, said stationary member being provided with a frame, a laminated core arranged within said frame, means for securing and retaining said laminated core in bled relation, and. means including a plurality of beam springs secured adjacent the 7 ends thereof to said frame and secured. intermediate the ends thereof to said core assembly retaining means for flexibly supporting said core 14. A dynamoelectric machine having a rotatable member and a stationary member, said. stationary member being provided with a frame, a laminated core arranged within said frame, means for securing and retaining said laminated core in assembled relation, andmeans including a plurality of beam springs secured adjacent the ends thereof to said frame and secured intermediate the ends thereof to said. core assembly retaining means for supporting said core directly on said frame, said beam springs being arranged in longitudinally p ced. apart sets and being arranged. in eircumferentially spaced apart relation in each of said sets.

15. A dynamoelectric a rotatable member and a member, stationarymember'beingprovidedwithaframeelesaid frame element, means for securing and. retainingsaidlaminatedcoreelementhi relatiomandmeansincludingapluralityofbeam springssecnredadjacenttheenmthereoftomie ofsaidelementsandsecm'edinterm the endsthereoftotheotherofsaidehmmtsfw said core element insaidframeele- ILOYD P. 

